Influence of Al declustering on the photoluminescent properties of Pr3 + ions in PbO–SiO2 glasses

Abstract Pr 3 + doped lead alumino silicate glasses with varying concentrations of Al 2 O 3 (from 5 to 10 mol%) have been synthesized. The IR and Raman spectral studies of these glasses have indicated that there is a gradual increase in the depolymerization of the glass network with an increase in the concentration of Al 2 O 3 . The optical absorption, luminescence spectra and fluorescence decay curves of these glasses were recorded at room temperature. The luminescence spectra of these glasses have exhibited the bands due to 3 P 0  →  3 F 2 , 3 F 3 , 3 H 6 , 3 H 4, 3 H 5 transitions. From these spectra, the radiative parameters viz., spontaneous emission probability A, the total emission probability A T , the radiative lifetime τ, the fluorescent branching ratio β of different transitions that originated from the 3 P 0 level of Pr 3 + ions have been evaluated. A considerable enhancement in the luminescence emission, especially in the red region corresponding to 3 P 0  →  3 H 6 , 3 F 2 transitions has been observed. The increase has been attributed to the possible admixing of wavefunctions of opposite parities and due to the declusterization of Pr 3 + ions by Al 3 + ions in the glass network. The branching ratio β has been observed to be the highest for the transition 3 P 0  →  3 F 2 and it is found to be ~ 50% for the glass mixed with 10 mol% of Al 2 O 3 . The CIE color coordinates for three glasses have been evaluated and found to be in the bright red region.